TrDE-KIPS AND SEA DRIFT. 379 



the east, they again turn down for lower latitudes and warmer 

 climates. This feature in them indicates, more surely than any 

 direct observations upon the currents can do, the presence, along 

 the African shores in the North Atlantic, of a large volume of 

 cooler waters. These are the waters which, having been first 

 heated up in the caldron (§ 726) of St. Roque, in the Caribbean 

 Sea, and Gulf of Mexico, have been made to run to the north, 

 charged with heat and electricity to temper and regulate climates 

 there. Having performed their offices, they have cooled down; 

 but, obedient still to the " Mighty Voice " which the winds and 

 the waves obey, they now return by this channel along the 

 African shore to be again replenished wdth warmth, and to keep 

 up the system of beneficent and wholesome circulation designed 

 for the ocean. 



CHAPTEE XYIII. 



§ 740-772. TIDE-RIPS AND THE SEA DRIFT. 



740. We never tire of the sea ; like the atmosphere, it is a labora- 

 The glories of the torv iu which wouders by processes the most exqui- 



sea, and the destiny . *^ ,• n ■ ^ t , n i -^ 



of the nautilus. Site are Continually going on. its liora and its 

 fauna, its waves and its tides, its currents and its salts, all in them- 

 selves afford profitable subjects of study and charming themes 

 for thought. But as interesting as they are individually, and as 

 marvellous too, they are not half so marvellous, nor nearly so 

 wonderful as the offices which, with their aid, the sea performs 

 in*the physical economy of our planet. In this aspect the sea, 

 with its insects, its salts, and its vapours, is a machine of the most 

 beautiful construction. Its powers are vast, multitudinous, and 

 varied. It is so stable and true in its work that nothing can 

 throw it out of gearing, and yet its compensations are so delicate 

 that the task of preserving them is assigned to the tiniest of its 

 inhabitants, and to agents apparently the most subtle and fickle. 

 They preserve its harmonies and make its adjustments, in beauty 

 and sublimity of effect, to vie with the glories of the heavens. 

 Take the tiny little nautilus, one of the oldest families in the 

 sea, for^ example. Where, inquires M. Lucien Dubois, do 

 they go in such fleets with their purple sails so nicely trimmed to 

 the breeze ? Who pilots them, and what master hand holds the 



